Respirators of the kind referred to are generally termed half-mask respirators and comprises a face mask formed of silicon or natural rubber covering the mouth and nasal passages of the user. Relatively large, heavy filter cartridges are usually disposed on the sides of the mask and are mounted on mask parts which house inhalation valves. Important criteria in the design of such respirators is that they are easy to don and adjust, that a reliable seal is provided between the mask and the face of the user, despite various facial configurations, and that they are nicely balanced and reasonably comfortable so that they can be used over a prolonged period of time. In addition, half-mask respirators of the kind described need to be compatible with protective eyewear and, in some cases, should be able to be integrated with a protective eye shield so that one unit affords protection from hazards to the eyes as well as providing protection from airborne vapors and particulates. A typical respirator of the kind referred to is found in U.S. Pat. No. 4,414,973, dated Nov. 15, 1983. The half-mask respirator disclosed in this patent provides upper and lower pairs of straps which are connected to the respirator by means of four spaced apart buttons which retain eyelets affixed to the ends of each of the pairs of straps. Both the upper and lower straps have independent adjustment means. The ends of the upper straps are interconnected by means of a hook-and-eyelet configuration which is apparently provided for the lower strap as well. The arrangement is somewhat awkward and is time consuming to adjust. If the upper straps slip from position on the user's head, the seal with the face can be readily broken.
U.S. Pat. No. 4,850,346, dated Jul. 25, 1989, discloses a respirator suspension system involving a crown strap comprising pairs of interconnected crown strap members joined together by junction pieces adjacent the side of the head with upper and lower side straps interconnected to the respirator by a yoke member. Although this arrangement provides a vast improvement in terms of comfort to the wearer and the maintenance of a good seal with the wearer's face, adjustment of the suspension by the individual is time consuming and is somewhat complicated and expensive to manufacture.
U.S. Pat. No. 3,040,741, dated Jun. 26, 1962, discloses a quick donning harness for an oxygen mask. This arrangement employs crown strap members which require independent adjustment through means of set screws and rely on coil springs to bias the mask onto the wearer's face. Although the mask assembly may be quickly donned once it is properly adjusted, initial adjustment is time consuming, and the arrangement is complicated and expensive. A separate neck strap is provided which is connected to the respirator by means of quick connect or snap fasteners, but this neck strap is apparently only used for suspending the mask around the user's neck when oxygen is not required.